1. Field of the Invention
The present invention relates to a data processing technique, and particularly to a data transfer technique.
2. Description of the Related Art
With a game device or another multimedia terminal, there is frequent need to read and write image data or audio data from and into a memory. In order to reduce the load on a CPU (Central Processing Unit), data transfer between a memory and an external input/output apparatus is often performed using DMA (Direct Memory Access) transfer. DMA transfer is a method for performing high-speed data transfer between a memory and an input/output apparatus without CPU intervention.
DMA transfer is executed after a CPU determines the necessity thereof and provides an instruction to a DMA controller. Therefore, DMA transfer could not have been directly controlled by a user program executed by the CPU, such as a program created by a user of a multimedia terminal. Meanwhile, in general data transfer, such as copying a character string, since a CPU core including an arithmetic circuit or the like primarily performs the transfer in response to a request from a user program, the CPU core has sometimes been subjected to a relatively heavy load.